Locomotive drifting control mechanism



Aug. 28, 1945,

R. P. DELANO, JR L OCOMQTIVE DRIFIING CONTROL MECHANISM Filed March 6, 1944 -2 Sheets-Sheet 1 INVENTOR.

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R. P. DE..ANQ JR v LOCOMOTIVE DRIFTING CONTROL MECHANISM Filed March 6, 1944 2 Sheets-Sheet 2 IN VEN TOR RA mo/vo PDa/wawz.

I I l! ,0 Z ATTORNEYS Patented Aug. 28, 1945 LoooMo'rIvE DRIFTING CONTROL I MECHANISM Raymond P. Delano, Jr., Baltimore, Md., assignor to Franklin Railwayi Supply Company, Inc., lNew York, N. Y., a corporation of New York Application March 6, 1944, Serial No. 525,131

6 Claims. (01. 121 -127) This invention relates to poppet :valve mechanismfor locomotives, and especially to control means for the intake valves providing for drifting operation of the locomotive, i. e., that opera'tion which is employed under certain conditions particularly when coasting or drifting down a long.- grade withoutpower. In the arrangement here contemplated, drifting operation ,provides for. holding certain of the Valves, preferably the intake valves, in open position so as to prevent the development of substantial differences in press sures in the oppositeends of the cylindenwand especially to avoidsuch reduced pressure or vacuum conditions as might. cause: induction of cinders into the cylinder from the smoke .box when the exhaust valves open.

In various poppet'va'lve gears heretoforeused, the function of drifting-has beenitaken care of in .a number of ways, one prior arrangement being the employment of specially: formed cams in the cam actuating mechanism. for the valves.

The arrangementofcthe present invention-includes means for holding the intermediatexor cam follower. levers away fromthe intake 'cams. 1 More specifically, thearfangementzof the invention -includes a: pairof swinging arms adapted to engage behind the free ends 'of the intermediate. levers for a pair of oppositelydisposedintake valves,

together-With a reciprocating operating. device for actuating the .swingllevers to hold the intake valves open. i

'It is an object ofthe invention to-provi de a construction of the type justlreferred to, which construction is sturdy and also reliable in -operation, the mechanism providing not only for positive actuation ofzthe swinging levers in directions to opentheintakevalves but also for positive actuation of the levers in: the opposite direction, thereby insuring that when the drifting mechanism is not in use the normal functioning of the valves is not interfered with. The invention also contemplates the provision of guide=meansfor the reciprocating operating member of the drifting mechanism, which guide means arelocated closely adjacent the point of interengagement between the swinging arms and the reciprocating member; whereby the guide means are positioned to take lateral thrusts which may at times occur, for instance if the drifting mechanism isoperated. at a time when one intake val'veof the pair is being held open by its associated intermediate lever,

The foregoing and other objects and advantages are brought out more fully herebelow in the descriptionofthe preferred embodiment of the invention which is illustrated in the accompanying drawings. In the drawings Figure 1 is a transverse sectionalview through a cam box incorporatingvalve operating parts to which the invention has been applied;

Figure 2 is a transverse sectional viewtaken I as indicated by the line 2-2 on Figure 1;

Figure 3-is a fragmentary view similar'to Figure. 2 but with certain parts-in a different position; and

Figure 4is a detail view of one of the parts.

Referring to the drawings, the cam'box is indicated at 3, this box being adapted-to be mounted above a cylinder andintermediatethe valve chests at the ends of the cylinder, in the manner disclosed "in, copending application of Julius Kirchhof and Raymond P. Delano,-Jr., Serial "No. 525,180 filed concurrently herewith. Tappetsd and-5 'project from the side walls of the box, fore and aft, to cooperate with the stems of the intake valves in the valve chests, the valve; parts not being herein illustrated since they form no part of the present inventionlper se. These'tappets are arranged to be: actuated-'by'intermediate levers '6 and 1 which are pivoted in the cambox at- 8 and 9, the levers carrying cam rollers land H which ride on the cam l2 mountedon cam shaft I 3. The pop-pet valves, as is customary, are provided with return springs for effecting clos ing movement, and these springs, as is well understood inthe art, act through the tappets 4 and 5 and thereby maintainthe cam rollers 'Hi and H in contact with the cam surface.

The cam employed mayeitherbe offan oscillating type or of a'rotating type "and maybe variously shaped, depending upon the particular mechanism, the type or shapeof the cam not' being of importance'from the standpoint of the present invention. It maybe mentioned, however, that the invention is particularly adaptable to an arrangemnt in which the cam is of the rotating type, the camshaft being axially *shift-' able in order to control the cutoff and converse the operation of the engine, in the mannermore fully set out in the copending application above mentioned. In a mechanism of this type in which the cam shaft is axially shiftable, the control Note, however, that the screw I4 is formed on a shaft I6 which, as seen in Figures 1 and 2, extends along the cam box above the cam shaft I3 and the intermediate levers 6 and I. The drifting mechanism is also situated in this same region and is arranged to straddle and thus accommodatethe shaft l6, as will further appear.

Above each of the intermediate levers 6 and 'l, a swinging arm I! is pivotally mounted on a fixed part l8 by pivots l8a, the lower end of this arm being adapted to engage behind the upper end of one of the intermediate levers. will be seen that at the right hand side of Fig. 2,

Thus, it

outward swinging movement of arm will abut the upper end of intermediate lever 6 and-thus move this lever and the associated tappet 4 outwardly, thereby lifting the cam roll ID from the cam and resulting in opening of the intake valve at the corresponding end of the cylinder.

by the mechanism described just below.

Toward the top of the cam box a cylinder I9 is arranged, a piston being vertically movable in the cylinder under the influence of pressure fluid introduced through port 2| (see Figure 1). When this piston moves downwardly it engages the upper end of the shaft 22 which projects downwardly and terminates in a double yoke 23-23, the central aperture in each part of the yoke being arranged to accommodate the control shaft l6 of the reversing and cutofi control mechanism.

A pair of pins 24 and 25 are carried between the lower ends of the two parts of the yoke and these pins cooperate with the swinging arms I! to effect movement thereof.

Each arm II has a surface 26 appropriately inclined with respect to the vertical motion of the yoke 2323 so as to cause the arm I! to swing outwardly upon downward movement of the cooperating pin 24 (or 25). This causes the opening of the intake valves as above mentioned.

Upward movement of yoke 23-23 and of the actuating piston 20 and the associated parts is brought about (upon exhaust of pressure through port 2|) by means of a compression spring 2'! reacting between a fixed abutment 28 and an abutment ring 29 which is fixed to the upper end of shaft 22. i 1

When the pines 24 are returned to the upper position, they engage projections 30 which are so shaped as to positively move the swinging arms inwardly away from the upper ends of the intermediate levers 6 and I.

With respect to the mechanism above described, attention is now called to the fact that thefixed parts l8-IB at opposite sides of the vertically movable yoke members 23 serve as guides for the vertical movement of the yoke members, these guides being extended downwardly to the region of the pins 24 and 25. The guides thus serve to take lateral thrusts which may arise at certain times, for instance when the drifting mechanism is actuated at a time whenone valve is closed and the opposite valve is being held open by its associated intermediate lever.

It may also be mentioned that the arrangement described is quite compact and provides for extension of the swinging arms in between the upper ends of the intermediate levers, not- This, outward swinging movement of arm I! is effected withstanding the fact that the free ends of the intermediate levers are relatively close to each other when both of the intake valves are closed. It is also of advantage that the pins 24 and 25 are tied togetherby the lower portion of the yokes 23 which lie below the shaft Hi.

It will beobserved that the arrangement also avoids vibration, chatter and wear because of the fact that the return spring 21 moves the yoke upwardly and the pins 24 and 25 thus swing the arms I! inwardly or toward each other until they interen'gage. Parts of the arms H the elves thus constitute limiting stops for the pward movement effected by the return spring 21.

It mayalso be mentioned that with surfaces such as indicated at 26 inclined in the manner described above, a very powerful valve opening force may be derived even from a relatively low pressure introduced above the actuating piston 20. This assures positive action in operation of the mechanism.

The control for the fluid pressure employed to actuate the operating piston 20 may be arranged in any desired manner;

I claim:

1. In steam distributing valve mechanism for a locomotive having cam actuated poppet valves, mechanism for opening a valve to provide for drifting operation, including a swinging arm adapted in one position to hold the valve open and in another position to release the valve for normal cam actuation, a reciprocable operating member, and an abutment carried by said member and adapted to bear against a surface of the arm which is inclined in a direction to move the arm to valve-open position.

2. A construction in accordance with claim 1 and further including guide means for the reciprocable member adapted to cooperate there with in a region adjacent the abutment for moving the swinging arm.

3. A construction in accordance with claim 1 in which the swinging arm further has another surface with which the abutment cooperates upon release movement to positively maintain the swinging arm in its released position.

4. A construction in accordance with claim 1 in which the valve actuating mechanism incorporates an intermediate lever and in which the swinging arm is adapted to engage behind the free end of the intermediate lever to effect opening movement of the valve.

5. In steam distributing valve mechanism for a locomotive having cam actuated poppet valves. mechanism for opening a valve to provide for drifting operation, including a reciprocable operating member, and an arm mounted to swing in a direction generally transverse the path 0 reciprocation of the operating member an adapted in one position to hold the valve ope and in another position to release the valve fo normal cam actuation, said arm and said member being interconnected by means of a pin and slot connection providing for positive actuation of the swinging arm in both directions between said positions thereof.

6. A construction in accordance with claim 5 and further including-a spring normally urging said reciprocable member to the position corresponding to release of the valve.

RAYMOND P. DELANO, JR. 

